The present invention relates to electronic organs and in particular to multi-purpose single chip LSI in which the complex data processing for the organ is accomplished.
With the advent of solid state electronics and the rapid growth of digital logic, it has become possible to perform many complex functions in connection with the operation of electronic organs and other electronic instruments. Whereas in the past very little was available in the way of automatic play features, the state of the art has now progressed to the point where even neophyte organists can play compositions previously playable only by much more advanced musicians. For example, many present day organs include circuitry for automatically playing fill notes in the solo manual simply by depressing a single chord playing key in the accompaniment manual and a single key in the solo manual. Furthermore, various note patterns on the solo and accompaniment manuals and bass patterns on the pedalboard can be stored in memories and recalled by the performer simply by playing the desired chord.
Heretofore, the electronics for such "easy play" features has been extremely complex and to reduce the difficulty and cost of manufacturing and servicing, there has been a steadily increasing trend toward integrating many of the circuit elements such as read only memories, dividers, individual keyers, etc. Although in some cases even major sub-systems of the organ have been integrated, the practical limitation of being able to obtain integrated circuit chips having no more than forty pins has proved to be an impediment to larger scale integration.